Old Charlie's left behind bars (4)
I believe the answer is:
aged
'old' is the definition.
(similar in meaning)
'charlie's left behind bars' is the wordplay.
'charlie' becomes 'c' (phonetic alphabet: alpha, bravo, charlie etc.).
'left' is a deletion indicator.
'behind bars' becomes 'caged' (I've seen this before).
'caged' with 'c' taken out is 'AGED'.
(Other definitions for aged that I've seen before include "Senescent" , "Getting on" , "not a modern copy" , "Like Uncle Arly" , "Grew older" .)